(in Polish, Zygmunt), in the Kingdom of Poland and the Grand Duchy of Lithuania:
Sigismund I the Old. Born Jan. 1, 1467; died Apr. 1, 1548. King of Poland and grand duke of Lithuania from 1506.
Under Sigismund I, Poland’s position in the West was weakened by the expansion to the East during the period 1507–37 (with some interruptions). In 1515, Sigismund concluded an agreement with the Hapsburgs that paved the way for the transfer of Bohemia and Hungary from the Jagiellonian family to the Hapsburgs. During the period 1519–21 he was involved in a struggle with the Teutonic Order; he subsequently permitted the master of the order to transform the lands of the order into the secular Duchy of Prussia, with the status of a Polish vassal. During Sigismund’s reign, Mazovia was annexed by Poland (1526).
Sigismund II Augustus. Born July 1, 1520, in Kraków; died July 7, 1572, in Knyszyn. King of Poland (crowned 1530) and grand duke of Lithuania from 1548; the last member of the Jagiellonian dynasty.
During the reign of Sigismund II, the crown lands that had been distributed to the magnates after 1504 were returned to the king. In 1564, Sigismund allowed the Jesuits into Poland, which marked the beginning of the Catholic reaction. The king took an active part in the struggle over the Baltic region during the Livonian War of 1558–83 and played an important role in the conclusion of the Union of Lublin in 1569.
Sigismund III Vasa. Born June 20, 1566, at the castle of Gripsholm, in Sweden; died Apr. 30, 1632, in Warsaw. King of Poland and grand duke of Lithuania from 1587.
Schooled by the Jesuits, Sigismund III aided in the establishment of the Catholic reaction in Poland. During the years 1592–99, he was also king of Sweden, where he strove to restore Catholicism; he was deposed by a national uprising, led by Duke Charles. Attempting to regain the Swedish throne, Sigismund waged a series of unsuccessful wars against Sweden during the years 1600–11, 1617–20, and 1621–29. From 1618 to 1620 he aided the Hapsburgs in their struggle against insurgent Bohemia. With the aid of the Brest Union of 1596, Sigismund sought to achieve the polonization of the Ukraine and Byelorussia. In 1604–05 he supported the First False Dmitrii, and in 1609, laying siege to Smolensk, he openly intervened in Russia; this intervention ended in defeat (seeDEULINO TRUCE OF 1618).